Uncooled Infrared Imaging Element Etching Holes Leak Current
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Solution Overview
Problem
Previous uncooled infrared imaging elements experience leak current issues due to the high voltage applied to SOI transistors, which causes an inversion layer at the interface between the gate and gate insulator, preventing the MOS transistor from being in a complete off-state and affecting pixel selection.
Innovation Solution
The uncooled infrared imaging element incorporates etching holes around the device and cavity regions on the support substrate to reduce the electric field and prevent the formation of the back channel inversion layer, thereby minimizing leak current by increasing the distance between the SOI region and the support substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage is applied to SOI transistor to drive diode-array, then signal intensity is improved, but leak current increases due to inversion layer formation
Solution Approach 1:
The patent extracts the harmful electric field effect by removing the support substrate from beneath the SOI transistor region, creating a suspended structure that eliminates the parasitic gate effect causing inversion layer formation and leak current
Solution Approach 2:
The patent introduces an intermediary structure (suspension layer or air gap) between the SOI transistor and the support substrate to prevent direct electric field interaction, thereby blocking the formation of inversion layer while maintaining transistor functionality
2Stability of the object's composition
If support substrate is placed close to SOI region, then device stability is improved, but electric field induction causes back channel formation
Solution Approach 1:
The patent removes the support substrate from the immediate vicinity of the SOI transistor, creating a physical separation that eliminates the parasitic gating effect while maintaining overall device stability through alternative support structures
Solution Approach 2:
The patent transitions from a planar close-proximity arrangement to a three-dimensional suspended configuration, positioning the support substrate at a different vertical level to eliminate electric field coupling while preserving mechanical stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces the leak current, allowing the MOS transistor to maintain a complete off-state and improving pixel selection accuracy by decreasing the electric field and carrier induction at the BOX interface.
Implementation Method 1
The uncooled infrared imaging element incorporates etching holes around the device and cavity regions on the support substrate to reduce the electric field and prevent the formation of the back channel inversion layer
Data Source
AI summary
An uncooled infrared imaging element includes a pixel region, a device region, and a support substrate. The pixel region includes heat-sensitive pixels. The heat-sensitive pixels are arranged in a matrix and change current-voltage characteristics thereof in accordance with receiving amounts of infrared. The device region includes at least one of a drive circuit and a readout circuit which includes a MOS transistor. The drive circuit drives the heat-sensitive pixels. The readout circuit detects signals of the heat-sensitive pixels. The support substrate is provided with a cavity region to be under pixel region and the MOS transistor.